#include<bits/stdc++.h>
#define int long long
using namespace std;

signed main() {
	int n, t = 0;
	cin >> n;
	for(int i = 0; ; i ++ ) {
		t += pow(2, i);
		if(t > n) {
			cout << i + 1 << endl;
			return 0;
		}
	}
	return 0;
} 
